/* @file u12_map.c
 * @brief functions to create and manipulate gamma lookup tables.
 *
 * Copyright (C) 2003-2004 Gerhard Jaeger <gerhard@gjaeger.de>
 *
 * History:
 * - 0.01 - initial version
 * - 0.02 - inverting map when scanning binary images
 *        - changed u12map_Adjust()
 * .
 * <hr>
 * This file is part of the SANE package.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as
 * published by the Free Software Foundation; either version 2 of the
 * License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston,
 * MA 02111-1307, USA.
 *
 * As a special exception, the authors of SANE give permission for
 * additional uses of the libraries contained in this release of SANE.
 *
 * The exception is that, if you link a SANE library with other files
 * to produce an executable, this does not by itself cause the
 * resulting executable to be covered by the GNU General Public
 * License.  Your use of that executable is in no way restricted on
 * account of linking the SANE library code into it.
 *
 * This exception does not, however, invalidate any other reasons why
 * the executable file might be covered by the GNU General Public
 * License.
 *
 * If you submit changes to SANE to the maintainers to be included in
 * a subsequent release, you agree by submitting the changes that
 * those changes may be distributed with this exception intact.
 *
 * If you write modifications of your own for SANE, it is your choice
 * whether to permit this exception to apply to your modifications.
 * If you do not wish that, delete this exception notice.
 * <hr>
 */

/**
 * @param  s - pointer to the scanner specific structure
 * @return The function always returns SANE_STATUS_GOOD
 */
static SANE_Status
u12map_InitGammaSettings(U12_Device * dev)
{
	int i, j, val;
	double gamma;

	dev->gamma_length = 4096;
	dev->gamma_range.min = 0;
	dev->gamma_range.max = 255;
	dev->gamma_range.quant = 0;

	DBG(_DBG_INFO, "Presetting Gamma tables (len=%u)\n",
	    dev->gamma_length);
	DBG(_DBG_INFO, "----------------------------------\n");

	/* preset the gamma maps */
	for (i = 0; i < 4; i++) {

		switch (i) {
		case 1:
			gamma = dev->adj.rgamma;
			break;
		case 2:
			gamma = dev->adj.ggamma;
			break;
		case 3:
			gamma = dev->adj.bgamma;
			break;
		default:
			gamma = dev->adj.graygamma;
			break;
		}

		for (j = 0; j < dev->gamma_length; j++) {

			val = (dev->gamma_range.max *
			       pow((double) j /
				   ((double) dev->gamma_length - 1.0),
				   1.0 / gamma));

			if (val > dev->gamma_range.max)
				val = dev->gamma_range.max;

			dev->gamma_table[i][j] = val;
		}
	}
	return SANE_STATUS_GOOD;
}

/** Check the gamma vectors we got back and limit if necessary
 * @param  s - pointer to the scanner specific structure
 * @return nothing
 */
static void
u12map_CheckGammaSettings(U12_Device * dev)
{
	int i, j;

	for (i = 0; i < 4; i++) {
		for (j = 0; j < dev->gamma_length; j++) {
			if (dev->gamma_table[i][j] > dev->gamma_range.max) {
				dev->gamma_table[i][j] = dev->gamma_range.max;
			}
		}
	}
}

/** adjust acording to brightness and contrast
 */
static void
u12map_Adjust(U12_Device * dev, int which, SANE_Byte * buf)
{
	int i;
	u_long *pdw;
	double b, c, tmp;

	DBG(_DBG_INFO, "u12map_Adjust(%u)\n", which);

	/* adjust brightness (b) and contrast (c) using the function:
	 *
	 * s'(x,y) = (s(x,y) + b) * c
	 * b = [-127, 127]
	 * c = [0,2]
	 */

	/* scale brightness and contrast...
	 */
	b = ((double) dev->DataInf.siBrightness * 192.0) / 100.0;
	c = ((double) dev->DataInf.siContrast + 100.0) / 100.0;

	DBG(_DBG_INFO, "* brightness   = %i -> %i\n",
	    dev->DataInf.siBrightness, (SANE_Byte) b);
	DBG(_DBG_INFO, "* contrast*100 = %i -> %i\n",
	    dev->DataInf.siContrast, (int) (c * 100));

	for (i = 0; i < dev->gamma_length; i++) {

		if ((_MAP_MASTER == which) || (_MAP_RED == which)) {
			tmp = ((double) (dev->gamma_table[0][i] + b)) * c;
			if (tmp < 0)
				tmp = 0;
			if (tmp > 255)
				tmp = 255;
			buf[i] = (SANE_Byte) tmp;
		}

		if ((_MAP_MASTER == which) || (_MAP_GREEN == which)) {
			tmp = ((double) (dev->gamma_table[1][i] + b)) * c;
			if (tmp < 0)
				tmp = 0;
			if (tmp > 255)
				tmp = 255;
			buf[4096 + i] = (SANE_Byte) tmp;
		}

		if ((_MAP_MASTER == which) || (_MAP_BLUE == which)) {
			tmp = ((double) (dev->gamma_table[2][i] + b)) * c;
			if (tmp < 0)
				tmp = 0;
			if (tmp > 255)
				tmp = 255;
			buf[8192 + i] = (SANE_Byte) tmp;
		}
	}

	if ((dev->DataInf.dwScanFlag & _SCANDEF_Negative) ||
	    (dev->DataInf.wPhyDataType == COLOR_BW)) {
		DBG(_DBG_INFO, "inverting...\n");

		if ((_MAP_MASTER == which) || (_MAP_RED == which)) {

			DBG(_DBG_INFO, "inverting RED map\n");
			pdw = (u_long *) & buf[0];
			for (i = dev->gamma_length / 4; i; i--, pdw++)
				*pdw = ~(*pdw);
		}

		if ((_MAP_MASTER == which) || (_MAP_GREEN == which)) {

			DBG(_DBG_INFO, "inverting GREEN map\n");
			pdw = (u_long *) & buf[4096];
			for (i = dev->gamma_length / 4; i; i--, pdw++)
				*pdw = ~(*pdw);
		}

		if ((_MAP_MASTER == which) || (_MAP_BLUE == which)) {

			DBG(_DBG_INFO, "inverting BLUE map\n");
			pdw = (u_long *) & buf[8192];
			for (i = dev->gamma_length / 4; i; i--, pdw++)
				*pdw = ~(*pdw);
		}
	}
}

/* END U12-MAP.C ............................................................*/
